diff --git a/cime_config/config_component.xml b/cime_config/config_component.xml
index 1ccec36..437fce4 100644
--- a/cime_config/config_component.xml
+++ b/cime_config/config_component.xml
@@ -134,6 +134,7 @@
     <default_value>constant</default_value>
     <values>
       <value compset="_CAM">diagnostic</value>
+      <value compset="E_CAM70">prognostic</value>
       <value compset="_MOM6%[^_]*MARBL-BIO.*_BGC%BPRP">prognostic</value>
       <value compset="_MOM6%[^_]*MARBL-BIO.*_BGC%BDRD">diagnostic</value>
       <value compset="_DATM%CPLHIST.*_MOM6%[^_]*MARBL-BIO">diagnostic</value>
diff --git a/param_templates/MOM_input.yaml b/param_templates/MOM_input.yaml
index 4cda4d5..87e5ab5 100644
--- a/param_templates/MOM_input.yaml
+++ b/param_templates/MOM_input.yaml
@@ -413,14 +413,6 @@ Global:
         datatype: real
         value:
             '"BASE_BIO_ON=TRUE" in $MARBL_TRACER_OPTS': $CCSM_CO2_PPMV
-    ATM_ALT_CO2_OPT:
-        description: |
-            "default comes from env_run.xml (OCN_CO2_TYPE)
-             Source of atmospheric CO2 concentration for MARBL.
-             valid values: constant, prognostic, diagnostic"
-        datatype: string
-        value:
-            '"BASE_BIO_ON=TRUE" in $MARBL_TRACER_OPTS': $OCN_CO2_TYPE
     ATM_ALT_CO2_CONST:
         description: |
             "default comes from env_run.xml (CCSM_CO2_PPMV)
diff --git a/param_templates/json/MOM_input.json b/param_templates/json/MOM_input.json
index 9bf459c..8314eb5 100644
--- a/param_templates/json/MOM_input.json
+++ b/param_templates/json/MOM_input.json
@@ -318,13 +318,6 @@
             "\"BASE_BIO_ON=TRUE\" in $MARBL_TRACER_OPTS": "$CCSM_CO2_PPMV"
          }
       },
-      "ATM_ALT_CO2_OPT": {
-         "description": "\"default comes from env_run.xml (OCN_CO2_TYPE)\n Source of atmospheric CO2 concentration for MARBL.\n valid values: constant, prognostic, diagnostic\"\n",
-         "datatype": "string",
-         "value": {
-            "\"BASE_BIO_ON=TRUE\" in $MARBL_TRACER_OPTS": "$OCN_CO2_TYPE"
-         }
-      },
       "ATM_ALT_CO2_CONST": {
          "description": "\"default comes from env_run.xml (CCSM_CO2_PPMV)\n Alternate atmospheric CO2 concentration for MARBL [ppm].\"\n",
          "datatype": "real",